Gas Absorption Studies in Microporous Hollow Fiber Membrane Modules

A comprehensive experimental investigation of gas-liquid absorption in a shell-and-tube type microporous hydrophobic hollow fiber device in a parallel flow configuration was carried out. Two modes of countercurrent gas-liquid contacting were studied, the wetted mode (absorbent liquid filled pores) and the nonwetted mode (gas-filled pores). The absorbent flowed through the fiber bore in most of the experiments. The systems studied include pure CO₂, pure SO₂, CO₂N₂ mixtures and SO₂-air mixtures. The absorbent was pure water. The absorption process was simulated for each case with a numerical model for species transport with and without chemical reaction. Laminar parabolic velocity profile was used for the tube-side flow, and Happel's free surface model was used to characterize the shell-side flow. The model simulations agreed well with the experimental observations in most cases. SO₂ removals as high as 99% were obtained in small compact contactors. High K_La and low height of transfer unit (HTU) values were obtained with hollow fiber contactors when compared to those of conventional contactors.